1. Technical Field
The present invention relates to a leak detection sensor and a system capable of monitoring the leak detection sensor remotely and, more particularly, to a leak detection device having a tape form, which can determine accurate locations of multiple leaks when the leaks are detected and monitor the detected leaks at a remote place and a remote monitoring system using the same.
2. Description of the Related Art
When water or oil leaks, various types of leak sensors for detecting water leakage and oil leakage are used.
Representative sensors can include a cable type leak sensor, a band type leak sensor, and a module type leak sensor.
The cable type leak sensor is a water leakage and oil leakage detection sensor for detecting the exposure of various types of liquid (e.g., water and oil) and informing a point at which liquid leaks accurately and rapidly.
When an electric current flows through a conducting wire, voltage is changed (i.e., the generation of a potential) due to the resistance of leaked liquid. Water leakage or oil leakage and an accurate location of the water leakage or oil leakage can be checked by detecting the change of voltage using a detection line.
However, such a cable type leak sensor is expensive in its installation cost, and a customer has a narrow selection width because the length of a sensor cable is determined (e.g., 7 M, 15 M, and 30 M). Furthermore, there are problems in that installation is difficult and an extra cost is necessary because an additional bracket must be used when installing the cable type leak sensor. Furthermore, there are problems in that the time taken to remove a leak after detecting the leak is long and it is difficult to connect the cable type leak sensor to an external device.
When an electric current flows through an electric wire, a resistance value is changed when water comes in contact with the electric wire. The band type leak detection sensor can detect whether water leaks or not based on a change of the resistance value.
A resistance value that can be controlled through the band type leak detection sensor is 0Ω to 50 MΩ, output is 100 mA at 30 V DC (maximum), a maximum wire length is 50 m, and a maximum length of the band type leak detection sensor is 10 m.
Such a band type leak sensor can detect water leakage in a wide area at low cost and can be easily installed, but is problematic in that an error incidence is high due to high humidity or an external impact and an accurate water leakage location cannot be easily checked. Furthermore, the band type leak sensor has problems in that it has product installation coarseness due to lack installation connection and a high investment cost must be used in order to use a network or PC. Furthermore, a customer has a limited selection width because the length of the leak detection sensor cable is limited (e.g., 1 M, 2 M, 5 M, 10 M, and 20 M).
Furthermore, the band type leak sensor is problematic in that a price is high as compared with performance, installation is difficult and additional expenses are necessary because an additional bracket to be fixed to the bottom needs to be installed when installing the band type leak sensor, and an alternative connection device in addition to a simple relay contact point method is not present when connecting the band type leak sensor to an external device.
The module type leak sensor includes photo sensors (e.g., a light-receiving unit and a light-emitting unit) within a plastic casing. The light-receiving unit receives a beam from the light-emitting unit in the state in which liquid has not been detected, but when the beam of the light-emitting unit detects liquid, the beam does not travel to the light-receiving unit due to a change of a refractive index.
At this time, the module type leak sensor detects water leakage. The module type leak sensor has input voltage of 12 V DC to 24 V DC, a response time of 50 ms, and a usual temperature of −10° C. to 60° C., and a sensor casing made of polypropylene.
The module type leak sensor can be easily installed, can detect a water leakage danger portion at low cost and generate an alarm and alarm lamp in itself irrespective of peripheral devices, and does not have an error attributable to humidity, but the module type leak sensor has problems in that it can check only whether a specific location leaks or not unlike a cable type leak sensor and it is difficult to connect the module type leak sensor to peripheral devices. Furthermore, the module type leak sensor has problems in that a lot of time is wasted in installing the module type leak sensor because an additional sensor fixing scheme must be planned and detection becomes difficult if a water leakage location is changed because only a specific portion of a water leakage danger area can be detected.
In order to solve the problems, the applicant of the present invention filed a number of applications regarding a tape type leak detection sensor, and an example of the application is Korean Patent Registration No. 10-0827385.
FIGS. 1 to 4 show the structure of a tape type leak detection sensor disclosed in Korean Patent Registration No. 10-0827385.
A leak sensing film 10 of a tape form includes an adhesive layer 20, a base film 30, a conductive line layer 40, and a protection film 50 which are sequentially stacked from the bottom to the top.
The adhesive layer 20 is attached to a position where a leak is generated and is formed in an adhesive tape form. The base film 30 is formed over the conductive line layer 40 and is made of PET, PE, PTFE, PVC, or other Teflon series for insulation purposes and so that the patterns of the conductive line layer 40 are formed on the base film 30 in a printing manner.
The conductive line layer 40 includes a plurality of resistance lines 41 and 42 and a plurality of signal lines 43 and 44 which are formed on a top surface of the base film 30 in a strip form. The pair of resistance lines 41 and 42 is spaced apart from each other and formed in parallel in the length direction of the leak sensing film 10, and the signal lines 43 and 44 are spaced apart from each other and formed in parallel in the length direction of the leak sensing film 10 outside the respective resistance lines 41 and 42.
Furthermore, the resistance line 41 and the signal line 43 are connected by an additional connector and the resistance line 42 and the signal line 44 are connected by an additional connector, at the end of the leak sensing film 10.
The protection film 50 is stacked over the conductive line layer 40 and configured to protect the patterns of the conductive line layer 40 from an external stimulus.
FIG. 2 is a diagram showing the state in which the conductive line layer 40 is formed. The conductive line layer 40 basically includes the resistance lines 41 and 42 printed using conductive ink and the signal lines 43 and 44 printed using a silver compound.
The resistance lines 41 and 42 and the signal lines 43 and 44 form a leak sensing circuit.
Furthermore, as shown in FIG. 3, sensing holes 51 are formed in the protection film 50 at specific intervals so that only the resistance lines 41 and 42 of the conductive line layer 40 are externally exposed through the sensing holes 51.
FIG. 4 is a diagram showing the state in which a plurality of the leak sensing films 10 is extended and connected and the plurality of the leak sensing films 10 is connected to a controller 2. If the distance for leak detection is relatively long, the plurality of leak sensing films 10 can be connected by a connector 70 so that they are extended in series.
Furthermore, the resistance lines 41 and 42 and the signal lines 43 and 44 are connected by a connector 60 so that they are connected to the controller 2 through a cable 1.
Therefore, when a leak L1 is generated in the leak sensing film 10, the leak L1 is introduced through the sensing holes 51 of the protection film 50 and the resistance lines 41 and 42 are electrified through the introduced leak L1.
Accordingly, a resistance value of the resistance lines 41 and 42 changes, and the changed resistance value is transmitted to the controller 2 through the signal lines 43 and 44. The controller 2 determines whether a leak has occurred or not based on a change of the resistance value and also determines the position of the leak L1 where the leak has occurred based on the amount of the changed resistance value.
That is, if the changed resistance value is great, it means that the position of the leak L1 where the leak has occurred is distant from the controller 2 by the amount of only the changed resistance value. If the changed resistance value is small, it means that the position of the leak L1 where the leak has occurred is close to the controller 2 by the amount of only the changed resistance value. Accordingly, an accurate location of the leak L1 can be determined based on a table value for the resistance value and the distance which is previously stored in the controller 2.
In such a case, however, if a leak detection range is a long distance, for example, 1 km or more, a plurality of the leak sensing films 10 connected in series is installed. If a plurality of leaks L1 and L2 is generated, the controller 2 can determine whether leaks have occurred or not, but cannot check the locations of the leaks L1 and L2.
That is, the controller 2 can check a position where a leak has occurred based on a change and amount of a resistance value when only one leak occurs. If the plurality of leaks L1 and L2 is generated, the controller 2 may check an erroneous resistance value for a different leak location because resistance values at locations where the leaks L1 and L2 have occurred are added and inputted to the controller 2.
In this case, there is a problem in that measures cannot be rapidly taken against the generation of leaks because an administrator must check a long-distance section one by one when the leaks are generated.